Particulate and dissolved matter as sources for pelagic sediments

• Compositional data for pelagic sediments, for denudation products from the continents and for marine biological matter can explain how much material is deposited on the ocean floor in dissolved and particulate form. Geochemical mixing models demonstrate that only 2 particulate phases, namely average biological matter and average continental matter, have to be mixed in various proportions to reproduce most pelagic sediments in regard to the elements Si, Al, Ti, Zr, V, Cu, Ni, Zn, Fe, and Cr. CaCO SUB-3 , B, Mn and to some extent Ba usually do not fit the models, since these elements partake in redissolution and migration processes. These latter processes to a large extent occur in hemipelagic and shelf areas. It is probable that such 'hemipelagic pumping' of elements over to the pelagic domain also affects constituents like Cu, P SUB-2 0 SUB-5 , and probably also Ni, Y, La and Co, but the effects are too small to show up in the mixing models. Improved mixing models are produced if a volcanic phase also is involved; the volcanic phase containing Fe, Mn, V and Ba, and possibly additional trace elements in proportions similar to those found in the East Pacific Rise deposits. The models suggest that continental detritus delivers most of the Al, Ti, Zr, Fe, Mn and V, and that biological detritus delivers the main fraction of the Ca, Sr, Cu, Pb, B, Ba, Ni, and Zn to the sediments. In most areas the main fraction of the SiO SUB-2 is terrigenous

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap -- Geokemi (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences -- Geochemistry (hsv//eng)

Nyckelord

Applied Geology

Tillämpad geologi

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